A lawyer for the two said the court decision “deals a decisive blow to the exploitation of children” and called on Zimbabwe’s legislature to set penalties for for the practice.

Nearly one-third of girls in Zimbabwe marry before their 18th birthday — some even before they turn 15 — when parents arrange their marriages.

The Constitutional Court’s ruling on January 20 banned marriage and other customary forms of unions for anyone under the age of 18. It also struck down a law that let girls marry at 16, but required boys to be at least 18.